As used herein, the term “smoking article” includes smokeable products such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn products.
Conventional filtered cigarettes generally comprise a rod of tobacco wrapped in a cigarette paper and a filter plug wrapped in a plug wrap. The filter plug and tobacco rod are connected using a tipping paper. The amount of smoke drawn through the filter depends on various factors, for example the air permeability of the cigarette paper, plug wrap and/or tipping paper. For instance, a cigarette paper of a high air permeability will permit airflow through the cigarette paper and will dilute the smoke more than a cigarette paper of lower air permeability. The air permeability of the cigarette paper used in cigarette manufacture is therefore a factor in controlling, at least, the smoke dilution of the cigarette.
One method of modifying the air permeability of paper is through an embossing process, as discussed, for example, in GB 1524211. The embossing process generally comprises exerting pressure at localised areas on the surface of the paper in order to open or stretch the fibrous structure of the paper to create indentations or holes in the paper. This has the effect of modifying the air permeability of the paper. Controlling the embossing process provides a means for controlling the air permeability of the paper.
Disadvantageously, the embossing process can cause a reduction in the tensile strength of the paper. This reduction in tensile strength can result in papers such as cigarette papers, plug wraps and tipping papers tearing as the paper is put under stress and/or strain during the cigarette and/or filter manufacturing process. This is undesirable and has the effect of limiting the rate of production.